Railway track circuit apparatus



Oct. 1940. P,`P. soslNsKl 2,218,125 I RAILWAY TRACK CIRCUITAPPARATUSFiled Aug. l5, 1934 INvgNToR Paul P. Sosmslfz H I S ATTORNEY PatentedGet. 15, 194i@ gPA'iil-I.NLT OFFICEQ RAILWAY TRACK CIRCUIT AIPARATU PaulP. Sosinski, Edgewood, Pa.,. assignor to The Union Switch & SignalCompany,

Swissvale,

Paga corporation of Pennsylvania I Application August 15, wetsuit! Np.739,946

21 Claims.

My invention relates to railway signaling apparatus of the typeinvolving track circuits, and has for anobject theprovisio-n, inapparatus of this type, of a novel and improved track circuitincluding'a relay which will-respond to the decrease in current suppliedto it when the train yenters the associated section, but which will notrespond to' track circuitcurrent of steady value or to gradual changesin the current supplied to the relay due for example to changes inballast conditions.

I Willv describe two `forms of apparatus embodying my invention, andwill then point outl the novel features thereof in claims. l5 In theaccompanying drawing, Fig. 1 is a diagrammatic View showing one form of'apparatus embodying my invention. Fig. 2 is a View showing amodification of al portion of the apparatus shown in Fig; 1, and alsoembodying my invention.

Similar reference characters refer to similar parts in each of theviews.

Referring first to Fig, 1, the reference characters I and ia designate'the track rails of a stretch of railway track along which traic normallymoves in the direction indicated by the arrow. These 'rails are dividedby insulated joints 2 to form a plurality of tracksections, of whichonly one complete section, D-E, is shown in the drawing. Traflcmo-vingthrough section D-E from left toi right is governed by a signal K,which, as here shown, is a light signal comprising a proceed lamp G, a.caution lamp Y, and a stop lamp R.

Section D-E is provided with a track circuit comprising a battery Hconnected across the rails at the exit end of the section and a neutralrelay P, a transformer T and a neutral relay A, all receiving'energyfrom the lrails at the entering end of thev section.` vRelay P has aholding 40 circuit which passes from rail I, through the primary 3 ofthe transformer T, a portion 6 of the operating winding of the relay P,a resistance?, a front Contact 8 of the relay'P, and a back contact 5 ofthe relay A to rail Ia. Relay P also has a pickup circuit which passesfrom rail I through the primary 3 of the transformer T, the entireoperating winding of the relay P, and a back contact I I of `a relay Sto rail Ia. The secondary 4 of the transformer T is connected, in serieswith a rectiiier Q, to the operating Winding of the relay A.

Relay S is a neutral relay controlled by a front contact 9 of the relayP and `energized by a battery I0. I y j 1 Associated-withrelays A, vPyand S. isa fourth relay F, which visa distant relay controlled by thefollowing cir'cuitzlirom terminal B ora suite able source of current atlocation E, throughfront contact I3 of relay S1 at location E, andWinding of relay F, 'to terminal Cl cf the same 'source of 5 current. jv f The proceed lamp G is provided with a circuit which passes lfromterminal B, through front Contact I2 of relayv S, front contact Il l ofrelay n F, and lamp Gto terminal C of the same source 10 of fcurrent.The caution lampY Y is provided fwith `a circuit which passes fromterminaljB, through front point of contact I2 of relay S,fback point ofContact I4 of relay F, and lamp Y to ter'- l' minal C. `The stop lamp R-is provided with a 15 circuit which'passesfrom terminal B, 'through backpoint of .contact I2 of relay S,kand lamp R toterminalC. y

The operation of the system is as follows: When section D-E unoccupied,relay A is de energized, relay P'is energized by currentvfro-m batteryH," and relay S is energized bycurrent from battery I0. If the sectionnextin advance isfalso unoccupied, relay F is energized. Lamp G willthen be lightedso that the signa-lwill in'- dicate proceed.' If,however; the sectionin advanl'oe'of'point'fE isoccupied-by a. train,relay F will be deenergized, so that'larnp Y will' be lighted and signalK will indilfate caution. e I will" now assume that a train entersAsection 30 D-E. l When this`occurs, the shunt aiforded by the wheels andaxles Yof suchv train will'suddenly reduce the "amount of currentflowing in primary 3 of transformer T, and this sudden change in theprimary current will induce an impulse of current in secondary 4' ofsuch polarity as to momentarily'energize relay A, opening back contact5. The momentaryopening of back contact 5 `will open the'holding circuitfor relay P which: Y in turn will'release relay S. The deenergization 40of relay S Ywilll open 4the -circuit for the proceed lamp G or thecaution lamp Y at front 'point of contact I2 of relay S and'will'closethe circuit for stop lamp'Rfat backpoint of contact'LI2. Signal Kwillthenndicate stop.A Relay P will re- 45 main downdue tothe trainshunt so long'assection D'-E is'occupied by a train. When the traintleaves section D-E, there will be a suddenfincre'asey in the amountofcurre'nt supplied to primary 3 of transformer T and this sudden change-in the primary current will'cause an impulse tobe induced in secondaryvI of a polarity opposite' to .that Igenerated whenr the train enteredthe section.A Rectier Q willprevent they ilow'of lthis vcurrent ofopposite polarity through the winding of relay A and relay A will not beenergized. Relay P will be energized by the pickup circuit whichincludes the full winding S and back contact Il of relay S. Theenergization of relay P will energize relay S through front contact 9 ofrelay P. The energization of relay S will open the pickup circuit andrestore the holding circuit for relay P. Relay F will have becomedeenergized due to thetrain entering the section in advance of sectionD-E, and so signal K will indicate caution until the train passes out ofsuch section in advance, when it will again indicate proceed.

Rectifier Q is not essential, however, because a momentary pickup ofrelay A, when the train leaves the section D-E, is of no consequence,since back contact 5 of relay A has ample time to reclose and thusestablish theholding circuit for relay P through iront contact 8 ofrelay P, before the pickup circuit for relay P is opened by back contactll of relay S. i

The operation of relay A is independent of the track energy level at theleft-hand end of section,D-E, and is `dependent only on the change intheamount of current supplied to transformer T when a train enters thesection. It follows that changes in the characteristics of the trackcircuit due to variations in weather or other conditions will not affect`the operation of this relay. Relay A is sufficiently sensitive torespond to a small change in the track circuit current such as wouldoccur when the track is shunted during wet ballast conditions,therefore, a relatively poor shunt would actuate relay A during dryballast conditions because of the relatively large change in the trackcircuit current. f Relay P, however, if relay A were not used, wouldrequire a relatively good shunt for releasing under dry ballastconditions. The combination of the two relays A `and P provides,therefore, for reliable shunting under all possible conditions oi thetrack.

`Referring now-to Fig. 2, the apparatus shown in this view is the sameas that shown in Fig. 1, except that relay A receives energy from asecondary winding 4fab of relay P wound in inductive relation to theoperating winding of relay P.

With this arrangement, the maximum energization'of relay P, which wouldordinarily obtain under dry ballast'conditions, must not begreat enoughto saturate the relay core as, otherwise, the train shunt may notproduce a Suflcient change in the ux to operate relay A. The apparatusshown in Fig. 2 is otherwise the same as that shown in Fig. 1'. l v

, Although I have herein shown and described only two'forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a sectionof railway track, a source of currentconnected across the rails of said section, a relay receivingenergy fromthe rails of said section and responsive to the steady value of currentwith which it isl supplied, and mearis also receiving energy from therails of said section and responsive to the change in value of `thecurrent received thereby due to the entrance'of a train into saidsection but not responsive to the steady value of such current formomentarily disconnecting said relay from at least one rail of saidsection. Y

.l 2. In combination,` a section of railway track,

a source of current connected across the rails of said section, a relayreceiving energy from the rails of said section and responsive to thesteady value of the current with which it is supplied, and a secondrelay also receiving energy from' the rails of said section andresponsive to the change in the value of the current received therebydue to the entrance of atrain into said section but not responsive tothe steady value of such current, said second relay having an arma-4ture actuating a contact for momentarily disconnecting said rst relayfrom one rail of said section.

3. In combination, a section of railway track, a source of currentconnected across the rails at one end of said section, a first relayreceiving energy from the rails at the other end of said section andresponsive to the steady value of current with which it is supplied, asecond relay, means also receiving energy from the rails at said otherend of the section for energizing said second relay when the value ofthe current received by said means is changed due to the entrance of atrain into said section, said means being incapable of responding to thesteady value of such current, and means controlled by said second relayfor decreasing the energization of said rst relay below the releasepoint thereof.

4. In combination, a section of railway track, a source of currentconnected across the rails of said section, a primary relay, a secondaryrelay, a holding circuit for said primary relay connected across therails of said section and including only a portion of the operatingwinding of the primary relay and a resistance, a pickup circuit for saidprimary relay also connected across the rails of said section andincluding the entire operating winding of said primary relay and a backcontact of said secondary relay, a circuit for said secondary relayincluding a front contact of said primary relay and a source of current,and means also receiving energy from the rails of said section andresponsive to the change in the value of the current received therebydue to the entrance 'of a train into said section for momentarilyopening said holding circuit for said primary relay.

5. In combination, a section of railway track, a source of currentconnected across the rails of said section, a primary relay, a secondaryrelay, a holding circuit for said primary relay connected across therails of said section and including only a portion of the Aoperatingwinding of the primary relay and a resistance, a pickup circuit for saidprimary relay also connected across the rails of said section andincluding the entire operating winding of said primary relay and a backcontact of said secondary relay, a circuit for said secondary relayincluding a front contact of said primary relay and a source of current,and a third relay also receiving energy from the rails of saidsectionand responsive to the change in the value of the current receivedthereby due to the entrance of a train into said section and having anarmature actuating a contact for momentarily disconnecting said primaryrelay from one rail of said section.

6. In combination, a section of railway track, a source of currentconnected across the rails of said section, a primary relay, a secondaryrelay, a holding circuit for said primary relay connected across therails of said section and including only a portion of the operatingWinding of the primary relay and a resistance, a pickup circuit for saidprimary relay also connected elfi fir!

across the rails of,y said section andincluding the entire operatingwinding of saidprimary relay and a back contact of said secondary relay,a circuit for said secondary relay including a front contact of saidprimary relay and a source of current, a third relay,'means alsoreceiving energy from the rails of said section for energizing saidthird relay when the value of the current received by said means ischanged due to the entrance of a train into said section, and meanscontrolled by said third relay for decreasing the energization of `saidprimary relay below the release point thereof.

7. In combination; a section of railway track,

a source of current connected across the rails of said section, aprimary relay having a holding circuit receiving energy from `therailsrof ,said section and including a front contact of the lprimaryrelay, a secondary relay controlled by a front contact of said primaryrelay, a pickup circuit for said primary relay receiving energy from therails of said section andincluding a back contact of said secondaryrelay, and means also receiving energy from th'evrails of said sectionand responsive to the change inthe value of the current received therebydue to the entrance of a train into said section for momentarily openingsaid holding circuit for said primary relay.

, 8. In combination, asection of railway track, a source of currentconnected across the rails of said section, a primary relay having aholding `circuit receiving energy from the rails of said section andincluding a front contact of the primary relay, asecondary relaycontrolled by a iront con- -tact of said primary relay, a pickup circuitfor said primary relay receiving energy from the rails of said sectionand including a back Ycontact of said' secondary relay, andatthird-relay also receiving energy fromV the rails of said sectionthrough a secondary Winding of said primary relay .and responsive to thechange in the value of the current received thereby due to the entranceof a train in said section, said third relay having an armatureactuating a contact for momentarily disconnecting said primary relayfrom one rail of said section.

9. In combination, a section of railway track, a source of currentconnected across the rails of said section, a primary relay having aholding circuit receiving energy from the rails of said section andincluding a front contact of the primary relay, a secondary relaycontrolled by a front contact of said primary relay, a pickup circuitfor said primary relay receiving energy from the rails of said sectionand including a back contact of said secondary relay, said primary relayhaving fa secondary winding in inductive relationV to the operatingwinding, a third relay connected to said secondary winding andresponsive to the change in the value of the current received therebydue to the entrance of a train in said section, said third relay havingan armature actuating a contact for momentarily disconnecting saidprimary relay from one rail of said section.

10. In combination, a section of railway track, a source of currentconnected across the rails of said section, a track relay receivingenergy from the rails of said section and responsive to the steady valueof current with which it is supplied, a transformer also receivingenergy from the rails of said section, and means including a'normallydeenergized auxiliary relay which becomes momentarily energized fromsaid transformer in response to a change in the energization of thetransformer occurring upon the' entrance of a traininto said section fordecreasing the energizationofisaid track relay' below the release pointthereof. V- n 11. In combination, a section of railway track, a sourceof current connected across the rails of said section, ajmain relayreceiving energy from the rails or said section and responsive to thesteady value of current with which it is supplied, a transformer havinga primary which receives energy from the rails of said section, anormally deenergized auxiliary relay receiving energy momentarilyV fromthe secondary of said transformer in response to a change in the energyreceived by said primary occurring upon the entrance of a train intosaid section, and means controlled by said auxiliary relay fordecreasing the energization of said main relay below the release pointthereof.

12. In combination, a section of railway track, a source of currentconnected across the rails of said section, a first relay receivingenergy from the rails of said section .and responsive to the lsteadyvalue of current with which it is supplied, a rectifier, a second relayhaving an operating circuit which includes said rectier, means ,also-receiving energy from the rails of said section for energizing saidoperating circuit when the value of the current received by said meansis changed due to the entrance of a train into said section, said meansbeing incapable ofenergizing said operating circuit in response to asteady value ofsuch current, and means controlled by said second relayfor decreasing( the energization of said first relay below the releasepoint thereof.

13. In combination with a section of railway track and a source ofcurrent connected across the rails of saidsection, a rrelayhavingan'op'erating winding receiving current from the rails of said sectionand having a second winding in in'- ductive relation with said operatingwinding, an auxiliary relay controlled by the current induced in saidsecond winding when said section becomes occupied by a train, `,andmeans governed by said auxiliary relay for controlling the supply ofcurrent to said operating winding.

14. A track circuit for railroads comprising, in combination, a sectionof railway track, a source of unidirectional current connected acrossthe track rails iat one end of said section, a track relay receivingenergy from the track rails at the other end of said section, atransformer having its primary winding included in said track circuit atsaid otherV end of the section, and an auxiliary relay :also at saidother end of the section energized only by current induced in thesecondary winding of said transformer, and operated in response to therelatively quick change of current in the track circuit caused by theentrance of a train into said section for decreasing the current throughsaid track relayto release its armature.

15. A track circuit for railroads comprising, in

combination, a unidirectional source of current direction is induced insaid secondary winding Y by the relatively quick change in the currentin `release its armature.

said track circuit caused bythe entranceof a train upon said trackcircuit, said contact when operated to said particular position4 actingto decrease the current through' said track relay to 16. In combination,a section of railway track, a source of current connected across therails of said section, a first relay receiving energy from the rails ofsaid section and responsive to the steady value of current with which itis supplied, a normally deenergized second relay, means for momentarilyenergizing said second relay due to the relatively high'rate of changeof current ow in said rst relay when the current through said rst relayis quickly decreased upon the entrance of a train into said section, andmeans controlled by said second relay when energized for decreasing theenergization of said first relay below the release point thereof.

17. In combination, a sectionof railway track, a source of energysupplying current to the rails of said section, a relay receivingcurrent from the rails of said section, and means responsive to the rateof change ofcurrent oW in said relay for completely disconnectingcurrent from said relay when the current through the relay is rapidlydecreased due to the entrance of a train into said section.

18. In combination, a section of railway track, a source of energysupplying current to the rails of said section, a relay receivingcurrent from the rails of said section, a transformer having its primaryalso receiving current from the rails of said section, and meansgoverned by the secondary of said transformer for completelydisconnecting current frorn said relay upon a. decrease in the currentowing in said primary due to the entrance of a train into said section.

19. In `a track circuit for railroads, the combination with a section of`railway track having a track relay connected thereto at one end of thesection and a source of unidirectional current connected thereto at theother end of the section, a normally' deenergized auxiliary relayseparate from said track relay and located at said one end of thesection, said auxiliary relay being eiective when operated to decreasethe current through'said track relay and thereby cause a release of itsarmature,r and means including a transformer also at'said one end of thesection for causing a momentary operation of said auxiliary relay inresponse to the relatively quick change in the current in said trackcircuit caused bythe entrance of a train into said section. j

20. A track circuit for railroads comprising in combination, a trackrelay at one `encl of the track circuit, a source of unidirectionalcurrent at the other end of the track circuit for energizing said trackrelay, an inductive device at said one end of the track circuit, and anormally deenergized auxiliary relay also at said one end of the trackcircuit receiving operating energy from the track circuit through saidinductive device in response to the relatively high rate of change inthe current in said track circuit produced by the entrance of a trainupon said track circuit for decreasing the current through said trackrelay and thereby causing a release of its armature.

21. In combination, a section of railroad track, a signal governingtrafc over said section, a source of energy connected across the railsat one end of said section, a track relay connected across the rails atthe other end of said section and responsive to the current 110Wtherein, electro-magnetic means responsive only to variations in currentflow in said track circuit to assume a particular magnetized conditionof only one polarity during such variations, and means jointlycontrolled by said track relay and said electromagnetic means forgoverning said signal.

PAUL P. SOSINSKI.

